Humans are evolving in a lot more ways than just biologically. Since the existence of mankind, humans have constantly changed their ways in order to fit in, strive, and achieve more in society.

Whether we are conscious of it or not, "survival of the fittest" is seen in our society in a variety of different ways as time goes by. Since the first American settler stepped foot on American soil, Americans have pushed frontiers and evolved in numerous categories, specifically in family structure. The structure of a family in the US has evolved considerably since the 1800's and early 1900's.

 A lot of what we believe to be normal now, would have been completely radical back in the early years of American society. This is not only seen in families, but also in race, technology, entertainment and other aspects of our culture. There is no doubt that America has evolved to a new socially acceptable family structure over the last two centuries. One of the biggest ways American families have evolved since the 1800's is in size. This can be attributed to birth control and economic reasons. In America women went from on an average having 7 babies to a little under 2. According to an article on why woman have fewer babies, historians believe that family budget has a lot to do with the decline in number of babies per woman. In the 1800's kids were taught at home or at their churches. Having a lot of kids during this time was seen as beneficial for moms, so they could have extra around the house. As public schools emerged in the U.S. children were of less use around the house, and more expensive to take care of, so it was a smarter economic decision to have fewer kids. A reporter for USA Today News asked a number of different married couples what they thought was the "ideal size" for a family. Most couples said that they thought having two children would be ideal, and if they wanted more than that it would be a tough financial decision. Birth control is arguably the biggest reason that the number of children per woman has dropped down to 2 on average. In the 1800's religious people were forbidden from having an abortion, and abortion is allowed to be preformed in 39 states if it is done by a licensed physician. For most women, abortion is not their desired method of birth control, and it is more of a last resort. In America things such as condoms, pills, surgeries and other things can be used as methods of birth control. Besides birth control and economic reasons, families also changed as society changed in a lot of different ways. 

For starters with the acceptance of interracial marriage. In 1664 a law was passed in Maryland that forbade slaves to marry whites. It was only up until the early 1960's that whites and other races were legally allowed to get married. Because interracial marriage became more popular and it was accepted by society, there were a lot more families that emerged with mixed races.